The proposed research is a first step in the exploration of variables which influence the value of activities for human beings. While traditional reinforcement research was focused on "primary" reinforcers as a distinct class more recent work has demonstrated that reinforcement value is a relative concept, and most activities can act as reinforcers under certain circumstances. One variable which has been central to research on the relativity of reinforcement is deprivation, and much of the controversy between different positions centers on the effect of deprivation on the value of a response. Research on reinforcement has also been typically done with non-human participants engaging in responses selected for the convenience of the recording apparatus. While this is an efficient way to produce research results it may not be the best way to find out about how human beings respond to the reinforcers which operate in their daily lives. The results of reinforcement and motivation research might be very different if it were done with human participants engaging in naturalistic activities. The research proposed here will examine the role of deprivation in determining reinforcement value by having human participants live in a self-sufficient laboratory for periods of 40 days. The experimental questions and procedures will be derived from traditional reinforcement research, but the response used and the living arrangements will be very much like the natural human environment. The experimental results will add to our understanding of basic reinforcement processes while at the same time making a great stride in the generalization to humans of reinforcements results from non-human participants.